Reflector-less nanoparticles doped optical fiber biosensor for the detection of proteins: Case thrombin

Abstract

A miniature biosensing platform based on MgO-based nanoparticle-doped optical fiber was developed for biomolecule detection. A single‑mode fiber with MgO-doped core was etched 1–2 mm from the tip, and Rayleigh backscattering signatures were analyzed. A thin gold layer increased sensitivity by 3.7×. The sensor showed sensitivity of 0.75–19.63 nm per refractive index unit over 1.3329–1.37649 RI, and detected thrombin concentrations from 0.625 μg/mL to 20 μg/mL using thiol‑modified DNA aptamers, demonstrating specificity, multiplexing potential, biocompatibility, and suitability for in vivo use.,